# DP: Turn on -D_FORTIFY_SOURCE=2 by default for C, C++, ObjC, ObjC++.

---
 gcc/doc/invoke.texi |    6 ++++++
 gcc/gcc.c           |    1 +
 2 files changed, 7 insertions(+), 0 deletions(-)

--- a/src/gcc/doc/invoke.texi
+++ b/src/gcc/doc/invoke.texi
@@ -5415,6 +5415,12 @@ also turns on the following optimization flags:
 Please note the warning under @option{-fgcse} about
 invoking @option{-O2} on programs that use computed gotos.
 
+NOTE: In Ubuntu 8.10 and later versions, @option{-D_FORTIFY_SOURCE=2} is
+set by default, and is activated when @option{-O} is set to 2 or higher.
+This enables additional compile-time and run-time checks for several libc
+functions.  To disable, specify either @option{-U_FORTIFY_SOURCE} or
+@option{-D_FORTIFY_SOURCE=0}.
+
 @item -O3
 @opindex O3
 Optimize yet more.  @option{-O3} turns on all optimizations specified
--- a/src/gcc/gcc.c
+++ b/src/gcc/gcc.c
@@ -810,6 +810,7 @@ static const char *cpp_unique_options =
  %{H} %C %{D*&U*&A*} %{i*} %Z %i\
  %{fmudflap:-D_MUDFLAP -include mf-runtime.h}\
  %{fmudflapth:-D_MUDFLAP -D_MUDFLAPTH -include mf-runtime.h}\
+ %{!D_FORTIFY_SOURCE:%{!D_FORTIFY_SOURCE=*:%{!U_FORTIFY_SOURCE:-D_FORTIFY_SOURCE=2}}}\
  %{E|M|MM:%W{o*}}";
 
 /* This contains cpp options which are common with cc1_options and are passed
